"Goggles or safety glasses are forms of protective eyewear that usually enclose or protect the area surrounding the eye in order to prevent particulates, water or chemicals from striking the eyes. They are used in chemistry laboratories and in woodworking. They are often used in snow sports as well, and in swimming. Goggles are often worn when using power tools such as drills or chainsaws to prevent flying particles from damaging the eyes. Many types of goggles are available as prescription goggles for those with vision problems. Motorcycle riding and other open-air activities: Prevents insects, dust, and so on from hitting the eyes. Winter sports: Protect the eyes from glare and from icy particles flying up from the ground." "Sunglasses provide improved comfort and protection against bright light and often against ultraviolet (UV) light. Photochromic lenses, which are photosensitive, darken when struck by UV light. The dark tint of the lenses in a pair of sunglasses blocks the transmission of light through the lens. Light polarization is an added feature that can be applied to sunglass lenses. Polarization filters are positioned to remove horizontally polarized rays of light, which eliminates glare from horizontal surfaces (allowing wearers to see into water when reflected light would otherwise overwhelm the scene). "